All posts by The Trauma Pro

Prevention

Best of EAST #5: Elderly Falls And Vision Problems

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Elderly falls have become a huge problem. There isn’t a night that goes by that we don’t admit at least two or three at our trauma center. There are at least a dozen factors that have been identified that are associated with falls, including:

  • Medications
  • Bone and muscle loss
  • Underlying medical conditions
  • Gait problems
  • Throw rugs and other environmental hazards
  • Visual problems

And many more! But let’s focus on that last one. Vision problems can be due to primary disease, such as glaucoma, or from lack of adequate correction of those problems, such as decreased visual acuity.

The group at West Virginia University is presenting a prevention paper next week. They prospectively studied patients older than 60 years who were admitted to their trauma service over a one year period. They wanted to determine the prevalence of undertreated or undiagnosed eye disease in the population, and to find out if using readily available screening tests could detect this and assist in prevention efforts.

A dilated ophthalmic exam was performed and used as the gold standard. The results were compared to a screening app administered by a trauma provider via an iPad (the eyeTests Easy app). This app can be used to test for visual acuity, macular degeneration, near vision, and astigmatism.

Here are the factoids:

  • A total of 96 patients were enrolled, with an average age of 75 and a predominant mechanism of fall in 79%
  • Significant abnormal vision was undiagnosed in 39% of patients and undertreated in 14%
  • The trauma provider app exam was 94% sensitive and 92% specific
  • Correlation was best on pupil exam (86%), visual fields (58%), and the macular degeneration test (52%)
  • A combination of visual fields and the Amsler grid were associated with significant abnormal vision

The authors concluded that unrecognized visual problems are common, and are present in 53% of their elderly trauma admissions. They also state the the trauma provider exam can identify abnormalities in “most cases” and can identify those who should be screened by an ophthalmologist.

My comments: This is an interesting study that compares a simple, app-based screen with a more sophisticated ophthalmology exam. However, it is not clear what “significant abnormal vision (SAV)” really is. The sensitivity and specificity numbers cited depend on this definition. Is it a positive answer to one of the screening questions? Evidence of macular degeneration? If so, how much? I’m sure that a lot of the elderly (and younger) population have some small irregularities in their vision, but what makes it significant?

The study does show that the app can be used as a screening tool due to the congruence with the “gold standard” ophthalmologic exam. And given that vision is one of the major factors associated with falls risk, it may be a cost-effective tool for reducing it.

Here are my questions for the authors and presenter:

  • What is you exact definition of “significant abnormal vision?” This is critical, because it determines the significance of the rest of your results. If the threshold is set too low, you will detect many anomalies but they may not be clinically significant. This definition needs to be as objective as possible so others can duplicate and take advantage of your work.
  • What do you recommend for workflow to incorporate this tool? Who should do it and when? Should the user focus on particular portions of the app (e.g. Amsler and visual fields, acuity)?
  • Describe your future plans for the longitudinal study mentioned in the abstract.

This is very interesting prevention work. I look forward to the nitty gritty details next week!

Reference: Stop the fall: identifying the 50% of geriatric trauma patients with significant vision loss. EAST 2021, Paper 11.

Trauma Systems

Best of EAST #4: Futile Trauma Transfers

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Level I and II trauma centers are regularly on the receiving end of what may be termed as “futile transfers.” These are patients who have sustained unsalvageable injuries and are initially seen at a lower level center. They are then transferred upstream where they succumb shortly (0-48 hours) after arrival.

As you might imagine, these patients can place a significant burden on resources at the Level I or II center. This is an even more acute situation given the large numbers of COVID patients who also require hospitalization and palliative care services these days.

The group at the University of Kansas sought to put some numbers on this phenomenon. They examined their own experience as one of two Level I trauma centers in the Kansas City metro area. They defined futile care as patients who died or were discharged to hospice care within 48 hours of arrival and who did not undergo operative, endoscopic, or interventional radiology procedures.

Here are the factoids:

  • A total of 1,241 patients were transferred in during the two year study period
  • Of these, 407 had stays of 48 hours or less, and 18 (1.5%) were deemed futile care according to their definition
  • The futile care patients tended to be much older (75 vs 61 years) and were much more severely injured (ISS 21 vs 8)
  • When transport and hospital charges were combined, the average total cost was $56,000
  • Total cost to this hospital was $1.7 million, and this was extrapolated to an annual cost of 27 million for the entire US

The authors concluded that these futile transfers are a small yet costly patient population. They suggested that accurately identifying these patients and providing resources to help referral hospitals figure out how to care for them would be helpful.

My comments: This is a very straightforward descriptive paper that details a problem that every high level trauma center sees on a regular basis. Older patients, typically those with critical head injuries that are beyond treatment, are transferred to the “big house.” The families are frequently told that there are no local resources to provide the care needed, and that the higher level center is their only chance. 

The families then have unrealistic expectations, and are inconvenienced by the travel involved. Wouldn’t it be better to just tell the family that the injury is a really bad one, and provide palliative / hospice care in the local community? Unfortunately, it’s not that simple. Many small hospitals do not have providers who are well-versed in this type of care. Thus, the suggestion to provide resources (people? training?) is a sound one.

This abstract highlights a problem we all face but seldom publicize. Hopefully this one will get us talking. And acting.

Here are my questions for the authors and presenter:

  1. What kind of resources do you think are needed to allow referral hospitals to care for these patients?
  2. How will these hospitals know when care is futile? Will there be an expectation to work with the receiving center to help determine this?

I enjoyed this paper and can’t wait to hear the details!

Reference: Futile trauma transfers: an infrequent but costly component of regionalized trauma care. EAST 2021, paper 9.

Imaging

Best of EAST #3: Spine MRI Usage After EAST Guidelines

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In 2015, EAST published their practice guidelines for spine clearance in the obtunded blunt trauma patient. Click here to view them. They stated that a high-quality CT scan can be used to remove (clear) the cervical collar in these patients. This avoids the use of the expensive and personnel-intensive MRI clearance.

The group at UCSF used the NTDB to review the use of MRI in such patients over an 11 year period. They focused on comatose patients (GCS < 8) with an AIS head > 3 and intubation for more than 72 hours. They used logistic regression to equalize confounders while examining the use of MRI over time, before and after the guidelines were published.

Here are the factoids:

  • More than 75,000 patients from 530 trauma centers were included
  • Patients who were older, Hispanic, uninsured, or involved in a car crash were less likely to undergo spinal MRI
  • Level I centers were more likely to use MRI for clearance than Level II centers
  • Patients evaluated after release of the practice guidelines were 1.7x more likely to undergo MRI for spine clearance (!!)

The authors concluded that spinal MRI use has been increasing since 2007 despite publication of the EAST guideline.

My comments: To me, this indicates one of the following:

  1. Nobody reads the EAST guidelines, or
  2. Trauma programs believe that they alone are able to figure out what is right, and everyone else is wrong

I suspect that it is #2. For some reason, trauma programs insist on doing it their own way despite what decent evidence shows. I think that this represents a defense mechanism to minimize the cognitive dissonance that comes with defying what is published in the literature.

I always encourage programs to borrow/steal what is already out there when crafting their own practice guidelines. Someone else has already done the work, why not take advantage of it? Typically, it’s just an excuse to continue doing things the way they’ve always been done.

This incessant reinventing the wheel becomes tiresome. And for once, I don’t have many questions or suggestions for the authors. Their evidence is pretty well laid out. 

My questions for the author / presenter are:

  1. Do you use MRI for spine clearance in your obtunded blunt trauma patients? And if so, WHY?
  2. Why do you think there are demographic and trauma center level disparities? Is it the teaching environment? Something else?

To everyone else, I say “get over yourself and read the literature!”

Reference: Assessing the e3ffect of the EAST guideline on utilization of spinal MRI in the obtunded adult blunt trauma patient over time. EAST 2021, Paper 7.

Complications, Resuscitation

Best of EAST #2: Blood Transfusion And Nosocomial Infection

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This abstract falls into the “interesting, but how can we use this bit of information” category. We’ve known that transfusing packed red cells raises nosocomial infection rates for at least 15 years. The group led by MetroHealth in Cleveland combined forces with the Vanderbilt trauma group to re-look at their data from the PAMPer trial with respect to trauma patients.

The PAMPer trial (Prehospital Air Medical Plasma) examined the effect of tranfusion of two units of plasma in the air ambulance on mortality, transfusion need, and complications. Half of the patients got plasma plus standard care, and the other half standard care alone.

This abstract uses PAMPer trial data to examine the impact of giving any amount of blood on nosocomial infection in these patients. These infections included pneumonia, bloodstream infection, C Diff colitis, empyema, and complex intra-abdominal infection.

The group retrospectively analyzed the prospectively collected PAMPer data and used logistic regression models to test for an association.

Here are the factoids:

  • A total of 399 patients with the usual trauma demographics were included (younger male, moderately injured, blunt mechanism)
  • Ten percent of patients died, and 23% developed nosocomial infections
  • Pneumonia was by far the most common complication (n=67) with all others in the low teens or below
  • Although only two thirds of patients received plasma, 80% were given PRBCs and 27% received platelets
  • Patients who received any amount of packed cells had a 2.3x increase in nosocomial infections, and the number given increased the rate of nosocomial infection (1.06x)

The authors concluded that patients in the PAMPer trial who received at least one unit of blood “incurred a two-fold increased risk of nosocomial infection” and that this risk was dose dependent.

My analysis: The biggest obstacle for me to buy into this work is the enrolled patient group. Studies in which you borrow someone else’s data are always a bit problematic. You have no control over the variables, as they’ve been determined by someone else.

In this case, the dataset could only be controlled for age, sex, and ISS. But what about all the other stuff that might have an impact on infections? Things like pulmonary injury, the 20% of patients who had penetrating injury, and severe TBI patients with their propensity to develop VAP.

The odds ratios of the associations were a bit on the low side. Sure, the overall nosocomial infection odds ratio was 2.37 but the confidence interval was 1.14 to 4.94. This is very wide and it means that the odds could have been anywhere from 1.14x to almost 5x. This suggests that the study group may not have been large enough to give us a clear picture. And the odds ratio for number of PRBC units vs infection was only 1.06 with a tighter confidence interval. So even if it is present, this association is very, very weak. I like to see ridiculously large odds ratios when reviewing observational studies like this where the input data is constrained.

My final comment on this study deals with its utility. These are trauma patients. They are bleeding. We’ve known that transfusions may increase the nosocomial infection rate in critically ill patients for at least 15 years. But we will still have to give the patients blood. So what are we to do?

Here are some questions for the authors and presenter:

  • Please comment on the limitations you faced using the PAMPer dataset. Were you satisfied with the range of variables available? Which additional ones would you have liked to work with?
  • Do you feel that the 399 patients provided enough statistical power for analysis? The confidence intervals are large and very close to the OR=1 line.
  • What should we do with your conclusions? Can we translate this into clinical practice?

One final note: the patients did not “incur increased risk.” Rather, there was an association with increased risk of infection. We really don’t know if it was from the blood or something else that was not recorded in the PAMPer dataset.

Reference: Dose-dependent association between blood transfusion and nosocomial infections in trauma patients: a secondary analysis of patients from the PAMPer trial. EAST 2021, Paper 3.

Abstracts, Resuscitation

Best of EAST #1: Ultramassive Transfusion Survival

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All right, let’s kick of this EASTfest with an abstract from one of the Eastern Association for the Surgery of Trauma multicenter studies. This one looked at outcomes after what they term “ultra-massive” resuscitation.

There are a number of definitions for “massive transfusion” which I’ve discussed before. They are basically trauma resuscitations in which the massive transfusion protocol is triggered. The group that designed this study defined ultra-massive resuscitation as one that entails transfusing at least 20 units of packed red cells within 24 hours.

The study focused on factors predicting survival in these patients. They used multivariate logistic regression as well as another regression tool, classification and regression tree analysis (CART). They used these tools to control for age, ISS, mechanism of injury, base deficit, and crystalloid use.

Here are the factoids:

  • A total of 400 patients were studied at 15 trauma centers over an eleven year period
  • Subjects were young (mean 37 years), male (81%), severely injured (mean ISS 34) and in shock
  • Median transfused products were 29u PRBCc, 23u FFP, and 24u platelets
  • Mortality was high with half dying in 24 hours and two thirds not surviving to discharge
  • Transfusion ratios > 1.5:1 for both RBC to plasma and RBC to platelets were strongly association with death
  • CART identified severe head injury, resuscitative thoracotomy, and low platelet count (< 169K / microliter) we association with high mortality
  • The best chance for survival occurred in those without a head injury, no thoracotomy, and higher platelet count

The authors concluded that the failure to meet balanced resuscitation goals was the main concern for mortality, and recommended more attention to meeting ratios.

My comments: I’m not so sure I’ve learned a lot from this abstract. I think we already knew that people with severe TBI or thoracotomy don’t do very well, especially if they need that much blood.

I also worry about the heterogeneity of the population. The variables that were controlled still offer quite a bit of variability in the injuries and condition of these trauma patients. I think this will make it difficult to come to many solid conclusions when looking at something as crude as mortality. 

Here are my questions for the authors and presenter:

  1. Why are there so few patients? An eleven year study with 15 centers participating means that each submitted less than 3 cases per year. Most busy Level I centers have many more than that in a single year. Was there some other kind of data selection or limitation that is not described in the abstract? Do you think there is enough power? See question 3 for more on this.
  2. How did you arrive at an admission platelet count threshold of 169,000/ul? This would seem to be a surrogate for something else going on, and I’m not sure what. But it just seems so arbitrary.
  3. The transfusion ratios are a bit confusing. For ratios less than 1.5:1, there are no error bars. Does this mean that every one of those patients survived? That’s remarkable if so. And the error bars for the groups with a ratio > 1.5:1 are perilously close to the 1 line, and they have quite a range. Is the statistical power really there to convincingly show a difference? This is the most interesting part of the abstract, so please expound upon it.
  4. Explain your use of CART. How did you determine the specific  determine the specific thresholds used in the CART model? Why did you choose to use this tool? For my readers, here is the tree presented in the abstract.
  5. What is the real message of the abstract? We already know that if patients who have a severe head injury or get their chest cracked are probably not going to make it. The transfusion ratio information is somewhat interesting, but there is better quality data out there that defines acceptable ratios. The platelet count information… interesting. What more do you have?

I think there is a lot of potential in this dataset once you overcome the small numbers. I’m very interested in the authors’ presentation!

Reference: Ultra-massive transfusion outcomes in a modern era: an EAST multicenter study. EAST 2021, Paper 1.